The Worthington Hepatocyte Isolation System provides a pre-optimized combination of enzymes that minimize lot-to-lot variation and improve the quality of the isolated hepatocytes. Each lot is use-tested by isolating hepatocytes from adult rat to assure performance, reliability, and yield of viable cells. Each kit includes single-use enzyme vials, balanced salt solution, buffer, culture media and an optimized protocol for five separate adult rat liver perfusions. The method is based on that described by Berry, M.N., modified by Seglen, P.O., and further optimized in conjunction with several collaborating researchers.